Deterrent ammunition projectile

ABSTRACT

Deterrent ammunition, including a projectile of soft elastic rupturable material, such as natural or synthetic rubber or plastic, having a charge of flowable material, such as finely divided particulate or powder, liquid or gas, carried in a cavity having relatively thin longitudinal rupture wall zones and thicker longitudinal strengthening zones bounding the cavity, with a generally ogive-forming nose section, having an over-all effectively more rigid, yet soft elastic, piston-forming nose end, the elastic thicker longitudinal wall zones enabling outward flexing thereof in response to rearward piston movement of the piston-forming nose end on target impact. The projectile may be carried in and fired from a conventional cartridge case and ejected from the cartridge by ignition of propellant in the cartridge, which may effect gas pressure directly on the projectile rear end or on a pusher element or elements engaging with the projectile.

nited States Patent 1191 Barr 1451 Feb. 11, 1975 DETERRENT AMMUNITIONPROJECTILE 221 Filed: July 13, 1973 21 Appl. No.: 378,855

[52] US. Cl l02/92.7, 102/926, 102/93 [51] Int. Cl. F42b 11/18, F42b31/00 [58] Field of Search 102/927, 41, 92.6, 92, 102/93 [56] ReferencesCited UNITED STATES PATENTS 2,983,224 5/1961 Prosen @1111. 102/933,156,187 11/1964 Batou 102/927 3,385,215 5/1968 .lungermann 102/9273,429,263 2/1969 Snyder et al 102/927 3,439,619 4/1969 Bock et al102/927 3,528,662 9/1970 Merchant et al. 102/927 3,650,213 3/1972 Abbottet al 102/927 3,714,896 2/1973 Young 102/927 3,733,727 5/1973 Jones etal 102/927 Primary ExaminerSamuel W. Engle Assistant ExaminerC. T.Jordan Attorney, Agent, or FirmReginald F. Pippin, Jr.

[57] ABSTRACT Deterrent ammunition, including a projectile of softelastic rupturable material, such as natural or synthetic rubber orplastic, having a charge of flowable material, such as finely dividedparticulate or powder, liquid or gas, carried in a cavity havingrelatively thin longitudinal rupture wall zones and thicker longitudinalstrengthening zones bounding the cavity, with a generally ogive-formingnose section, having an overall effectively more rigid, yet softelastic, pistonforming nose end, the elastic thicker longitudinal wallzones enabling outward flexing thereof in response to rearward pistonmovement of the piston-forming nose end on target impact. The projectilemay be carried in and fired from a conventional cartridge case andejected from the cartridge by ignition of propellant in the cartridge,which may effect gas pressure directly on the projectile rear end or ona pusher element or elements engaging with the projectile.

23 Claims, 5 Drawing Figures PATENTED FEB] 1 I975 PIC-3.3

DETERRENT AMMUNITION PROJECTILE This invention relates to deterrentammunition, and more particularly to personnel deterrent ammunitionprojectiles which are rupturable on impact, and which may be launchedagainst a target with rupture occurring on impact, for cushioning of theimpact forces, and, if desired, may deliver a flowable material onimpact rupture. The projectile may be launched directly against riotingpersonnel to provide an impact shock or sting to the target personneland, if so desired, to deliver a desired fiowable material in thevicinity of the target personnel with substantially reduced hazard ascompared to conventional ammunition.

Various materials and arrangements have been employed in an effort tocontrol rioting or other disorderly personnel, while minimizing ultimatedamage to the personnel being controlled. Fire hoses have been used forthis purpose, but have been generally abandoned or found to be generallyunsatisfactory, due to the very substantial injury potential, as well asthe unfavorable image cast on firefighting units by their associationwith this tactical weapon. Water cannons have also been tried, and whilethe water cannon has advantages over the fire hose approach, itnevertheless has very substantial injury-producing potential.Technically, the fire hose and the water cannon systems utilize asimilar principle of projecting a variable intensity water jet stream tounbalance and/or disarm an individual. Water cannons and fire hose alsoare large, heavy, cumbersome and normally require several persons foroperation.

Also, various mechanisms have been employed, including launchablegrenades and shells, for delivery of a desired charge of control agentto a target area. However, these prior mechanisms have variousdisadvantages, and the launched grenades or shells have conventionallybeen quite lethally hazardous to target personnel in the event of impactwith such personnel.

It is an object and feature of the present invention to provide animproved personnel control deterrent ammunition projectile whichprovides relatively low lethality hazard to the target personnel, whileenabling a substantial degree of deterrent control of such personnel bycushioned impacting of the target personnel with the impact-rupturableprojectile, and, if so desired, by impact rupture delivery of a flowablecharge of material to the target zone, through impacting of therupturable projectile, the projectile carrying a charge of flowabledispersable material which is discharged on projectile impact contactwith the target personnel or other target in the vicinity of targetpersonnel.

It is a further object and feature of the invention to provide animproved low-hazard riot control ammunition which enables the deliveryof a marking or other desired liquid to the vicinity of a rioting personor persons, and which will rupture in an impact-cushioning fashion onimpact, with good dispersion characteristics.

Still further objects, features and advantages will become apparent toone skilled in the art from a reading of the following description of apreferred embodiment, constructed in accordance with the invention,taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a longitudinal section view, on line 1-1 of FIG. 2, of aprojectile according to the invention.

FIG. 2 is a view in cross-section on line 2-2 of FIG. 1.

FIG. 3 is a cross-section view similar to FIG. 2, illustrating amodification.

FIG. 4 is a cross-section view of a modified rear end section of aprojectile according to the invention.

FIG. 5 is a perspective view, partially cut away for clarity, of afurther modification utilizing a separate removable lateral reinforcingsleeve external of the projectile.

Referring now in detail to the figures of the drawing, a projectile 11is provided, preferably formed in two major sections, including a noseand side wall section 21 secured to a rear section 31.

The nose and side wall section 21 is formed with a piston-forming noseend wall portion 23 and a side wall portion 25. Side wall portion 25 hasweakened zones formed by spaced grooves or depressions in a facethereof, preferably the inner surface, as by longitudinal grooves 27 asshown. The thicker wall sections 29 between the longitudinal grooves 27form elastically flexible longitudinal columnar and radial strengtheningzones, and the ungrooved nose portion 23 forms a more rigid, yet elasticand shock cushioning, piston portion which is depressed rearwardly toeffect outward bending of the annular side wall portion 25 uponimpacting of the nose with a target or other object. I

The thicker relatively more rigid rear section 31 has a shoulder 33, 34onto and against which the nose and side wall section 21 is secured, asby adhesive or other suitable securing medium. The sections 21, 31 arepreferably formed of natural or synthetic rubber, or other similarmaterial, (preferably having a durometer of approximately 30-50), and asuitable rubber adhesive may be utilized. In an embodiment employing aprojectile made of silicone rubber, a suitable example being siliconerubber sold by Dow Corning under the name RTV, a suitable adhesive hasbeen found to be a silicone rubber adhesive marketed by Dow Corningunder the designation RTV-732.

The base or rear section 31 has a rifling band 35 formed thereon toimpart stabilizing spin to the projectile when the projectile is firedfrom a rifled barrel.

.To provide additional strength, particularly for rifling engravingaction, to the soft elastic rubber material, glass fibers or otherstrengthening fibers may be added to the rubber molding compound used inthe base or rear section 31. While the rifling band is preferably on thebase or rear closure section 31, a rifling band may alternatively beformed on a portion of the side wall portion 25, although this is not asdesirable as it is preferred to employ a forward section 21 which isdevoid of such strengthening media as glass fibers which are desirableto be utilized for rifling band forming section.

A cavity C is formed within and bounded by the nose and side wallsection 21 and the rear section 31, in which may be disposed a suitablecharge of flowable material, such as finely divided particulate orpowder, e.g., tear gas powder, or liquid, P for dispersal throughrupture openings formed along grooves 27 on impact of the projectilewith a target or other object. Alternatively, while delivery anddispersal of a charge of flowable material P is preferred and mostadvantageous, the projectile may also be used without a charge ofmaterial in the rupturable cavity C, in which event the personnel impactdeterrent utility of the soft rupturable projectile is employed, withthe hydraulic gas compression and lateral expulsion and columnar bendingcushioning advantages flowing from the piston nose 23 and bendablycollapsible columnar zones 29 and rupturable lateral weakened zones 27of the side wall 25, being utilized for desired shock absorption so asto minimize personnel permanent damage or lethality on impact.

The projectile 11 may be suitably mounted in and fired from aconventional cartridge having ignitable propellant therein, and apusher, of conventional or other desired design, may be utilized toimpart propellant gas forces to the projectile if so desired. Securingof the projectile 11 in a cartridge case may be effected as by crimpingof the forward end zone of the case (not shown) about and into grippingrelation with the annular surface 37 rearward of rifling band 35.

In operation, the projectile 11 will be ejected from a barrel bore,preferably a rifled bore for suitable spin stabilization and accuracy,and impact of nose 23 with a target or other object will effect relativerearward movement of the piston-forming nose 23 toward the forwardlymoving piston-forming base or rear section 31, and/or vice versa, asgenerally indicated in phantom line in FIG. 1, effecting shock-absorbingcolumnar collapse of stiffening column zones 29 and shockabsorbingcompressive action on the powder, liquid, or gas contents P, in cavityC, all of which results in rupture of weakened zones 27 and lateralejection of the flowable material P from the cavity C through rupturedzones 27. Impact forces may also ultimately effect rupture along theconnection zone between sections 21 and 31, at shoulder 33, 34, andthereby further effect ejection of the material P.

A modification is illustrated in cross section in FIG. 3, in which thelongitudinally weakened zones are formed by external longitudinalgrooves in the outer annular surface of the side wall and nose section121, and extending to the piston-forming nose portion 123. The thickerand columnar stiffer soft elastic zones are indicated at 129.

A further modification is illustrated in FIG. 4, in which a reinforcingannulus in the form of a cup or shell 231a forms the effective rear faceand annular rifling band surface 235 of the rear section 231 for aprojectile having a forward side wall and nose section 21, as in FIGS. 1or 3, suitably secured thereto as at shoulder 233, 234 as in theembodiment of FIG. 1. The shell annulus 231a may be suitably formed ofthermoplastic resin, preferably low-density material such aspolyethylene, or nylon or other thermoplastic resin may be employed ifdesired for a given utilization. The resin may be suitably reinforcedwith glass or other reinforcing fibers incorporated in the moldingcompound, if desired, particularly as an aid in rifling engraving uponfiring and travel of the projectile along a rifled barrel bore. In thisembodiment, the silicone rubber or other molding compound for maincentral and forward portion of base or rear section 231 is preferablymolded in situ in the previously formed cup or other effective annulus231a, thereby aiding in securement thereto, although separate formationand subsequent assembly may be effected, with set back compressiveforces on the main central rubber portion of base 231 serving to providefrictional gripping action between the contiguous interfacing wallsurfaces of this rubber central portion and the cup annulus 231a uponfiring and riflingeffected spin-up action on the cup annulus 231a.

In FIG. 5, a further modification is illustrated, in which the barrelbore and rifling engagement, during travel of the projectile 311 along abarrel bore, is effected by a split sleeve annulus 341, whicheffectively encompasses the major longitudinal extent of the projectile,including the rear or base section 333 and the cylindrical or straightside wall portion of side wall and nose section 321. In this embodiment,the rifling band on the projectile is eliminated and the sleeve 341serves to engrave the rifling and effect spin-up to itself and theprojectile 311, which may otherwise take the form of one of thepreceding embodiments of FIGS. 1 or 3, or other suitable embodimentwithin the teachings hereof. Sleeve 341 may be suitably splitlongitudinally and will be expanded radially into rifling engravingengagement with a barrel bore as a function of set-back forces on theprojectile during firing. A pusher, preferably an obturating pusher discof standard construction and utilization, not shown, may be suitablyemployed to transmit forward propulsion forces from the propellant gasesof a cartridge to the projectile 311 and sleeve 341 upon firing of theprojectile, and this pusher may also engage the rifling inrotation-imparting relation to aid in imparting rotation to theprojectile 311 through forward driving action on and frictional facecontact with the rear face of the rear section 333 of the projectile andthe rear face of the expandible sleeve 341. The sleeve 341 also aids inprotecting the projectile during travel along the barrel bore, as wellas providing a desired reduction of any tendency of the rubber or othersoft elastic projectile walls to grip and unduly retard the projectileduring travel along the barrel bore. Upon exit from the barrel the splitsleeve 341 will separate and be discarded from the projectile undercentrifugal and other forces thereon, and by utilizing a suitably lowdensity material for the sleeve 341, the secondary projectile dangerstherefrom may be minimized, the high drag/low mass relationship thenresulting in relatively quick dissipation of the sleeve travel energy,and the low mass will itself minimize danger of damage on anyinadvertent impact. To this end, the sleeve is preferably formed of lowdensity material such as low density polyethylene, or other suitably lowdensity material such as other thermoplastic or other resins.

While the invention has been described with respect to several physicalembodiments, it will be apparent that various modifications andimprovements may be made without departing from the scope and spirit ofthe invention. For instance, the projectile of FIG. 5, without a riflingband, may have its spin imparted thereto solely by frictional or otherinterengagement with a driving pusher disc or a sabot if so desired. Insuch event, or otherwise, the rear face of base or rear section 333 maybe provided with grip enhancing means, such as radial spoked or othersuitable recess in or on its surface. Accordingly, the invention is notto be limited by the illustrative embodiments, but only by the scope ofthe appended claims.

I claim:

1. Deterrent ammunition, comprising,

a projectile formed by a rupturable flexible side wall section with acavity formed therein and having an annular bounding wall with annularlyspaced plural longitudinally extending thinner weakened rupturablelongitudinal wall zones which are substantially weaker thaninterconnecting relatively thicker structurally reinforcing side wallsections between said thinner weakened zones,

said side wall section being open at its rear end for securement to theforward end of a separate base section,

nose and base sections closing said cavity at its forward and rearwardends,

and a flowable dispersable material charge in said cavity for dispersalupon impact of said projectile with a target,

said base section being a separate body secured at its forward end tothe open rear end of said rupturable flexible side wall section along anannular rupturable shouldered connection zone therewith,

said base section being relatively substantially more rigid as a bodythan said wall section and forming a forwardly moving piston actingagainst said charge and said side wall section upon impact of said nosewith a target mass, to thereby enable rupture along one or more of therespective zones.

2. Deterrent ammunition according to claim 1,

said nose and wall sections being formed of relatively soft elastic,material rupturable at said thinner weakened zones in response tointernal cavity pressures thereon as a function of impacting said nosesection with an object; and said thicker side wall sections beingoutwardly flexible in response to said internal cavity pressure andrearward impact movement of said nose section.

3. Deterrent ammunition according to claim 2,

said wall section having a plurality of convex wall sections, withlongitudinally grooved sections therebetween and forming saidlongitudinally extending thinner wall zones.

4. Deterrent ammunition according to claim 2,

said nose section having a generally ogive shape and including arelatively thick piston nose portion, with a relatively flexible annularwall section extending rearward of said piston nose section and forminga flexible connection between said piston nose section and said basesection.

5. Deterrent ammunition according to claim 1,

said base section being substantially thicker and stronger than saidflexible side wall section,

said base section being reinforced with glass fiber filling.

6. Deterrent ammunition comprising a projectile formed by a rupturableflexible side wall section with a cavity formed therein and having anannular bounding wall with annularly spaced plural longitudinallyextending thinner weakened longitudinal wall zones which aresubstantially weaker than interconnecting relatively thickerstructurally reinforcing side wall sections between said thinnerweakened zones,

nose and base sections closing said cavity at its forward and rearwardends,

and a flowable dispersable material charge in said cavity for dispersalupon impact of said projectile with a target,

said projectile having a rifling band thereon,

and a relatively rigid reinforcing annulus forming a portion of saidbase section,

said rifling band being formed on said reinforcing annulus.

7. Deterrent ammunition according to claim 6, said reinforcing annulusbeing a reinforcing cup.

8. Deterrent ammunition according to claim 7, said reinforcing cup beingformed of thermoplastic resin.

9. Deterrent ammunition according to claim 8, said reinforcing cup beingformed of glass-filled thermoplastic resin.

10. Deterrent ammunition, comprising a projectile formed by a rupturableflexible side wall section with a cavity formed therein and having anannular bounding wall with annularly spaced plural longitudinallyextending thinner weakened rupturable longitudinal wall zones which aresubstantially weaker than interconnecting relatively thickerstructurally reinforcing side wall sections between said thinnerweakened zones, said side wall section being open at its rear end forsecurement to the forward end of a separate base section, and nose andbase sections closing said cavity at its forward and rearward ends,

said base section being a separate body secured at its.

forward end to the open rear end of said rupturable flexible side wallsection along an annular rupturable shouldered connection zonetherewith,

said base section being relatively substantially more rigid as a bodythan said wall section and forming a forwardly moving piston actingagainst said charge and said side wall section upon impact of said nosewith a target mass, to thereby enable rupture along one or more of therespective zones.

11. Deterrent ammunition according to claim 10,

said nose and wall sections being formed of relatively soft elasticmaterial rupturable at said thinner weakened zones in response tointernal cavity pressures thereon as a function of impacting said nosesection with an object, and said thicker side wall sections beingoutwardly flexible in response to said internal cavity pressure andrearward impact movement of said nose section.

12. Deterrent ammunition according to claim 11,

said wall section having a plurality of convex wall sections, withlongitudinally grooved sections therebetween and forming saidlongitudinally extending thinner wall zones.

13. Deterrent ammunition according to claim 11,

said nose section having a generally ogive shape and including arelatively thick piston nose portion, with a relatively flexible annularwall section extending rearward of said piston nose section and forminga flexible connection between said piston nose section and said basesection.

14. Deterrent ammunition according to claim 13,

said base section being substantially thicker and stronger than saidflexible side wall section.

15. Deterrent ammunition according to claim 13,

said base section being formed of rubber being reinforced with glassfiber filling.

l6. Deterrent ammunition according to claim 11,

said nose section having a generally ogive shape and including arelatively thick piston nose portion, with a relatively flexible annularwall section extending rearward of said piston nose section and forminga flexible connection between said piston nose section and said basesection,

said base section being formed of glass fiber filled material.

17. Deterrent ammunition according to claim 10,

said nose and wall sections being formed of relatively soft elasticmaterial rupturable at said thinner weakened zones in response tointernal cavity pressures thereon as a function of impacting said nosesection with an object, and said thicker side wall sections beingoutwardly flexible in response to said internal cavity pressure andrearward impact movement of said nose section,

a relatively rigid reinforcing annulus disposed about said projectile,

said relatively rigid reinforcing annulus having a circumferentiallyweakened longitudinal separation zone enabling radial expansion of saidannulus for rifling engraving engagement with a barrel bore as afunction of set-back forces on said projectile during firing.

l8. Deterrent ammunition according to claim 17,

said reinforcing annulus being longitudinally split along said weakenedseparation zone.

19. Deterrent ammunition according to claim 18,

said reinforcing annulus being a longitudinally split sleeve separablefrom said base, side walls and nose sections of said projectile afterexit from a rifled barrel bore.

20. Deterrent ammunition, comprising a projectile formed by a rupturableflexible side wall section with a cavity formed therein and having anannular bounding wall with annularly spaced plural longitudinallyextending thinner weakened longitudinal wall zones which aresubstantially weaker than interconnecting relatively thickerstructurally reinforcing side wall sections between said thinnerweakened zones,

and nose and base sections closing said cavity at its forward andrearward ends,

said nose and wall sections being formed of relatively soft elasticmaterial rupturable at said thinner weakened zones in response tointernal cavity pressures thereon as a function of impacting said nosesection with an object, and said thicker side wall sections beingoutwardly flexible in response to said internal cavity pressure andrearward impact movement of said nose section,

said projectile having a rifling band thereon,

and a relatively rigid reinforcing annulus forming a portion of saidbase section, said rifling band being formed on said reinforcingannulus.

21. Deterrent ammunition according to claim 20, said reinforcing annulusbeing a reinforcing cup.

22. Deterrent ammunition according to claim 21, said reinforcing cupbeing formed of thermoplastic resin.

23. Deterrent ammunition according to claim 22, said reinforcing cupbeing formed of glass-filled thermoplastic resin.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT N0. 3,865,038 DATED February 11, 1975 INV ENTOR(S) 1 Irwin R.Barr It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

In the heading [73] add ---Assi,qnee: AAI Corporation, Cockeysville,

Maryland Column 3, Line 50, change "resin" to ---resins--- Signed andScaled this Thirty-first Day of May 1977 [SEAL] Attesr:

RUTH C. MASON Arresting Officer C. MARSHALL DANN UNI'TED STATES PATENTAND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT N0. 3,865,038DATED February 11, 1975 TNVENTOR(S) Irwin R. Barr It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In the heading [73] add --Assignee: AAI Corporation, Cockeysville,

Maryland Column 3, Line 50, change "resin" to ---resins--- Signed andScaled this Thirty-first Day of May 1971 [SEAL] Arrest:

C. MARSHALL DANN Commissioner oflarents and Trademarks

1. Deterrent ammunition, comprising, a projectile formed by a rupturableflexible side wall section with a cavity formed therein and having anannular bounding wall with annularly spaced plural longitudinallyextending thinner weakened rupturable longitudinal wall zones which aresubstantially weaker than interconnecting relatively thickerstructurally reinforcing side wall sections between said thinnerweakened zones, said side wall section being open at its rear end forsecurement to the forward end of a separate base section, nose and basesections closing said cavity at its forward and rearward ends, and aflowable dispersable material charge in said cavity for dispersal uponimpact of said projectile with a target, said base section being aseparate body secured at its foRward end to the open rear end of saidrupturable flexible side wall section along an annular rupturableshouldered connection zone therewith, said base section being relativelysubstantially more rigid as a body than said wall section and forming aforwardly moving piston acting against said charge and said side wallsection upon impact of said nose with a target mass, to thereby enablerupture along one or more of the respective zones.
 2. Deterrentammunition according to claim 1, said nose and wall sections beingformed of relatively soft elastic, material rupturable at said thinnerweakened zones in response to internal cavity pressures thereon as afunction of impacting said nose section with an object; and said thickerside wall sections being outwardly flexible in response to said internalcavity pressure and rearward impact movement of said nose section. 3.Deterrent ammunition according to claim 2, said wall section having aplurality of convex wall sections, with longitudinally grooved sectionstherebetween and forming said longitudinally extending thinner wallzones.
 4. Deterrent ammunition according to claim 2, said nose sectionhaving a generally ogive shape and including a relatively thick pistonnose portion, with a relatively flexible annular wall section extendingrearward of said piston nose section and forming a flexible connectionbetween said piston nose section and said base section.
 5. Deterrentammunition according to claim 1, said base section being substantiallythicker and stronger than said flexible side wall section, said basesection being reinforced with glass fiber filling.
 6. Deterrentammunition comprising a projectile formed by a rupturable flexible sidewall section with a cavity formed therein and having an annular boundingwall with annularly spaced plural longitudinally extending thinnerweakened longitudinal wall zones which are substantially weaker thaninterconnecting relatively thicker structurally reinforcing side wallsections between said thinner weakened zones, nose and base sectionsclosing said cavity at its forward and rearward ends, and a flowabledispersable material charge in said cavity for dispersal upon impact ofsaid projectile with a target, said projectile having a rifling bandthereon, and a relatively rigid reinforcing annulus forming a portion ofsaid base section, said rifling band being formed on said reinforcingannulus.
 7. Deterrent ammunition according to claim 6, said reinforcingannulus being a reinforcing cup.
 8. Deterrent ammunition according toclaim 7, said reinforcing cup being formed of thermoplastic resin. 9.Deterrent ammunition according to claim 8, said reinforcing cup beingformed of glass-filled thermoplastic resin.
 10. Deterrent ammunition,comprising a projectile formed by a rupturable flexible side wallsection with a cavity formed therein and having an annular bounding wallwith annularly spaced plural longitudinally extending thinner weakenedrupturable longitudinal wall zones which are substantially weaker thaninterconnecting relatively thicker structurally reinforcing side wallsections between said thinner weakened zones, said side wall sectionbeing open at its rear end for securement to the forward end of aseparate base section, and nose and base sections closing said cavity atits forward and rearward ends, said base section being a separate bodysecured at its forward end to the open rear end of said rupturableflexible side wall section along an annular rupturable shoulderedconnection zone therewith, said base section being relativelysubstantially more rigid as a body than said wall section and forming aforwardly moving piston acting against said charge and said side wallsection upon impact of said nose with a target mass, to thereby enablerupture along one or more of the respective zones.
 11. Deterrentammunition according to claim 10, said nose and wall sections beingformed of relatively soft elastic material rupturable at said thinnerweakened zones in response to internal cavity pressures thereon as afunction of impacting said nose section with an object, and said thickerside wall sections being outwardly flexible in response to said internalcavity pressure and rearward impact movement of said nose section. 12.Deterrent ammunition according to claim 11, said wall section having aplurality of convex wall sections, with longitudinally grooved sectionstherebetween and forming said longitudinally extending thinner wallzones.
 13. Deterrent ammunition according to claim 11, said nose sectionhaving a generally ogive shape and including a relatively thick pistonnose portion, with a relatively flexible annular wall section extendingrearward of said piston nose section and forming a flexible connectionbetween said piston nose section and said base section.
 14. Deterrentammunition according to claim 13, said base section being substantiallythicker and stronger than said flexible side wall section.
 15. Deterrentammunition according to claim 13, said base section being formed ofrubber being reinforced with glass fiber filling.
 16. Deterrentammunition according to claim 11, said nose section having a generallyogive shape and including a relatively thick piston nose portion, with arelatively flexible annular wall section extending rearward of saidpiston nose section and forming a flexible connection between saidpiston nose section and said base section, said base section beingformed of glass fiber filled material.
 17. Deterrent ammunitionaccording to claim 10, said nose and wall sections being formed ofrelatively soft elastic material rupturable at said thinner weakenedzones in response to internal cavity pressures thereon as a function ofimpacting said nose section with an object, and said thicker side wallsections being outwardly flexible in response to said internal cavitypressure and rearward impact movement of said nose section, a relativelyrigid reinforcing annulus disposed about said projectile, saidrelatively rigid reinforcing annulus having a circumferentially weakenedlongitudinal separation zone enabling radial expansion of said annulusfor rifling engraving engagement with a barrel bore as a function ofset-back forces on said projectile during firing.
 18. Deterrentammunition according to claim 17, said reinforcing annulus beinglongitudinally split along said weakened separation zone.
 19. Deterrentammunition according to claim 18, said reinforcing annulus being alongitudinally split sleeve separable from said base, side walls andnose sections of said projectile after exit from a rifled barrel bore.20. Deterrent ammunition, comprising a projectile formed by a rupturableflexible side wall section with a cavity formed therein and having anannular bounding wall with annularly spaced plural longitudinallyextending thinner weakened longitudinal wall zones which aresubstantially weaker than interconnecting relatively thickerstructurally reinforcing side wall sections between said thinnerweakened zones, and nose and base sections closing said cavity at itsforward and rearward ends, said nose and wall sections being formed ofrelatively soft elastic material rupturable at said thinner weakenedzones in response to internal cavity pressures thereon as a function ofimpacting said nose section with an object, and said thicker side wallsections being outwardly flexible in response to said internal cavitypressure and rearward impact movement of said nose section, saidprojectile having a rifling band thereon, and a relatively rigidreinforcing annulus forming a portion of said base section, said riflingband being formed on said reinforcing annulus.
 21. Deterrent ammunitionaccording to claim 20, said reinforcing annulus being a reinforcinG cup.22. Deterrent ammunition according to claim 21, said reinforcing cupbeing formed of thermoplastic resin.
 23. Deterrent ammunition accordingto claim 22, said reinforcing cup being formed of glass-filledthermoplastic resin.